Reciprocity Corrections
If the exposure time is shorter than 1/10,000 seconds or longer
than 1 second, it is necessary to calculate and adjust for
reciprocity failure.
Exposure time indicated by
Exposure scale
Compensation
Exposure
1 second (or over)
x2
2 seconds
5 seconds (or over)
x5
25 seconds
50 seconds (or over)
x12
600 sec or 10 min.
Note: 1. All information mentioned above is based on ASA 100 film
speed.
2. Some practice will be required to relate the times given in
this chart to your particular camera and film. Keep a careful
record of the light conditions and the exposure times for
every photograph you take, so that future adjustments may
be made easily.
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If you don't want to use a light meter, the following guide may
help: 1-3 seconds under bright sunlight, 4-20 seconds for shade;
4-10 minutes for cloudy, for indoor or night scene, use 15-45
minutes or more. These estimated exposure times are based on
ASA100 film.
Trigger the Shutter
1. To expose, simply slide the shutter (A) to open. When the
exposure time is up, close it by sliding it back to cover the
pinhole.
2. If you use high speed film or a zone plate version camera, the
exposure time may be less than 1 second. This time you may
need to open the shutter (A) and cover the pinhole/zone plate
with hat and put it back to cover the pinhole as fast as you can.
3. If you have the optional cable release adaptor, you can open
the shutter manually by sliding it, or by attaching a cable
release to trigger the shutter as in the "B" mode on any
ordinary camera.
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04/23/2013, 05:49 PM
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